Transfer-hydrocracking of vacuum residue

Hydrocracking of Arabian Heavy vacuum residue conducted in the presence of metal supported active carbon catalyst gave large amount of distillates (70%) with small hydrogen consumption. Especially, the Yalloum coal derived active carbon catalyst showed high cracking activity. The yield of asphaltene in the product oil was very low, whereas the coke yield was relatively high. In the metal-free active carbon system, the coke yield and the content of olefins, sulfur compounds and asphaltene in the product oil were higher than those of the metal-supported active carbon system. These results suggest that asphaltene in feed oil was adsorbed on the metal supported active carbon catalyst and was decomposed or dehydrogenated on it to form coke and hydrogen atoms. The hydrogen atoms formed migrated on the carbon surface to reach the metal site and transferred to free radicals, olefins or organo sulfur compounds.